The sacroiliac (SI) joint 10 is located between the sacrum 11 and the hip bones 12, known as the ilium, in the human body, as shown in FIG. 1, and functions to transmit forces from the spine 14, including vertebrae 14a, intervertebral discs 14b and the coccyx 14c, to the lower extremities. The sacroiliac joint 10 is supported by ligaments and muscle. The sacroiliac joint 10 can degenerate over time, requiring a fusion procedure to stabilize the degenerated segment. For example, one condition, degenerative sacroiliitis, results in a narrow joint space with bone spur formation. Iatrogenic (i.e., induced by treatment) procedures, such as iliac bone graft damaging ligaments of the joint and/or previous fusions, can also cause degeneration, requiring sacroliac joint fusion. Alternatively, infection, ligamentous disruption due to pregnancy, and/or trauma causing fracture dislocation may require a sacroiliac joint fusion procedure to provide sufficient stabilization to allow the patient to achieve a normal lifestyle.
Traditionally, surgeons use screws, often with the combination of rods, to link the sacroiliac joint together. A standard sacroiliac stabilization procedure consists of the following steps: a posterior exposure to the spine, the removal of degenerated sacroiliac joint material, the posterior placement of a stabilizing screw/joint construct, or the lateral placement of screws directly through the sacroiliac joint, and, finally, the substitution of bone graft into the joint, which subsequently fuses to stabilize the sacroiliac joint region.
To place stabilizing screws laterally in the sacroiliac joint region, a surgeon makes a secondary incision and drives screws through the external table of the iliac crest through the sacroiliac joint and into the sacrum. The trajectory of these screws is critical. If a surgeon places screws on a path too anterior, the screws may penetrate the sacral wall and damage the vessels that lie just beyond. If a surgeon places screws on a path too posterior, the screws may penetrate the sacral wall or sacral foramina and damage the nerves of the cauda aquina. Achieving and maintaining a precise trajectory can be difficult in the limited operating space. Therefore, a device to precisely guide the trajectory of the screws is optimal in a sacroiliac joint stabilization procedure.